Connect with us
botrytis in greenhouse tomato botrytis in greenhouse tomato

Crop protection

Identifying and controlling botrytis in greenhouse tomato production

Botrytis, or gray mold, caused by the fungus, Botrytis cinerea, can cause significant losses in high tunnel and greenhouse tomato production if not controlled properly.

Botrytis, or gray mold, caused by the fungus, Botrytis cinerea, can cause significant losses in high tunnel and greenhouse tomato production if not controlled properly.

The pathogen can rapidly spread during periods when structures are closed and when relative humidity remains high for long periods of time.

Botrytis cinerea
Identifying and controlling botrytis in greenhouse tomato production 88

This often occurs when outside weather remains cool and damp while heating is needed. Gray mold is favored by temperatures from 64° to 75° F and requires only high humidity (not leaf wetness) to become established. The pathogen has a large host range and once established in an enclosed structure it can be very difficult to control (University of Massachusetts). The fungus can survive/overwinter as mycelia or sclerotia in plant debris and in organic soil matter (North Carolina State University).

Botrytis is ubiquitous (e.g., found everywhere) and prefers to attack senescing or injured plant tissue. Botrytis cinerea is an excellent saprophyte as well as a pathogen. This means that any dying or dead tissue on tomato plants (or any other plant in the structure) can easily become infected. The pathogen will attack flowers, fruit (at the stem end of infected fruit or by causing ghost spot), leaves, and stems; importantly, plants that have recently been suckered or pruned.

Stem infections occur during periods of high humidity through leaf scars, cracks, and pruning wounds. Spores can remain dormant for up to 12 weeks within pruning leaf scars and are triggered to germinate during plant stress. Stem lesions may expand in concentric rings to girdle the entire stem causing wilting above the infection site (NCSU).

Botrytis can be controlled by the management of environmental conditions, sound cultural practices, and fungicide applications.

As stated above, gray mold is favored by temperatures from 64° to 75°F and requires only high humidity (not leaf wetness) to become established. Keep relative humidity as low as possible by a combination of heating and venting in the evening, particularly when warm days are followed by cool nights. Maintain adequate airflow with horizontal fans. Avoid the overcrowding of plants.

Maintain proper fertility programs. Run regular tissue tests. Gray mold is known to be favored by low calcium levels. In particular, calcium to phosphorus levels of less than 2:1 may make the tomato plant more susceptible to gray mold (UMASS). Keep floors and structures clean of any plant debris or organic matter. All pruned plant material needs to be removed immediately. Do not work on wet plants, prune plants in the early afternoon allowing wounds to dry quickly (NCSU).

Control options

Controlling botrytis begins with proactive cultural practices, recognizing conditions that are conducive for its development, and symptoms on infected plant materials. There are a number of conventional and organic fungicides labeled for its control in the greenhouse and high tunnel. Please see Table E-11 in the 2020/2021 Mid-Atlantic Commercial Vegetable Production Recommendations Guide.

Identifying and controlling botrytis in greenhouse tomato production 89
Greenhouse ventilation

Provide good ventilation, both day and night, to keep plants dry and air humidity low. Good air circulation improves ventilation and reduces the chance of condensation forming. Moving air through the crop helps keep the plant and air temperatures the same.

To improve ventilation:

  • open the vents in the greenhouse when temperatures rise to replace warm moist air with cool air
  • heat the greenhouse at night to reduce humidity (when heated, air absorbs moisture)
  • maintain low humidity at night with a cycle of heating and cooling (plant transpiration where water vapour is released at night causes humidity levels to rise in greenhouses)
  • install a humidity sensor to allow automatic opening and closing of the vents.

To improve air circulation:

  • use fans to move air within the greenhouse
  • choose a plant density that will allow good air movement between the plants
  • prune regularly to remove laterals, and old and dense leaves to assist air movement through the plants
  • avoid leaf wetness by never spraying crops in the afternoon or at any time if the weather is such that drying by night will be difficult.

Rutgers University


Crop protection

Greenhouse ginger has a stronger flavor than imported ginger

In Belgium, CRU is now offering prime fresh ginger on its markets. It is grown locally and sustainably. It is also cultivated pesticide-free and with a minimum of organic fertilizers. The ginger has a stronger flavor than imported ginger.

Also, its carbon footprint is kept as low as possible. This prime ginger is the result of sustainable innovation. Colruyt Group initiated that in cooperation with the REO cooperative and the Provincial Experimental Centre for Vegetable Production.


As a retailer, the Colruyt Group is becoming increasingly aware of food’s impact on people’s health and the planet. It is constantly working on making its products more sustainable. Then its customers can deliberately make sustainable choices.

In this context, Colruyt Group and its collaborators launched this pilot project to grow fresh prime ginger in Belgium. This is a project of the Colruyt Group’s food innovation team for CRU. The ginger’s environmental footprint is reduced thanks to its local, sustainable cultivation.


Local, sustainable farming
This ginger is grown in a greenhouse at the Provincial Vegetable Research Center. Two REO cooperative growers also cultivate it under a non-heated plastic tunnel and greenhouse, also non-heated. The ginger was planted in mid-May and is harvested in the fall.


The growers used a minimal amount of organic fertilizer and no pesticides during cultivation. Growing locally reduces CO2 emissions, as shorter trips are needed to get the product to end-users. This ginger goes from the field to Belgian plates. This product usually comes from Asia and South America, increasing its carbon footprint.


Fresh, top-quality ginger
The Belgian is harvested when the plant’s foliage is still green, so it has no chance to harden or form a skin. That gives the ginger a distinct aroma and flavor. It is very juicy with no fiber and is fresher than the imported versions.

These tubers are uprooted and washed and can be eaten right away. This top-quality ginger has a limited shelf life. This pilot project’s first crop has both good quality and yield – so it was a success. Scaling it up and further sustainability is, therefore, being evaluated.


Exclusive to CRU
People can now buy this high-quality Belgian ginger for a short while at CRU’s three fresh markets in the country. Then it’s back to waiting for the next harvest. So, CRU clients are the first to get the opportunity to taste this local product.


Ginger is very trendy. Because it is so healthy, more and more people are using this root. It is also ideal for flavoring dishes, in fresh but also in syrup or powder form. Taste and user tests have already confirmed that this Belgian ginger outshines the usual product from Brazil, Peru, and China. The Colruyt Group is therefore proud to market this locally-grown, tasty, ultra-fresh product.


Continue Reading

Crop protection

New research greenhouse for natural crop protection developer

Thorben, in the foreground, at the new facility

Valto received the keys to a greenhouse with 17 departments on the Hoefweg in De Lier, with which director Thorben Looije is taking the next step in his growth ambition.

Valto is a Dutch family business specialising in natural crop protection products. Their best-known product, V10, protects tomato plants against the highly damaging pepino mosaic virus. The research into new, natural crop protection products has so far been done at various locations.

After the imminent modifications to the new greenhouse complex, Valto’s researchers will be able to carry out larger tests on several crops and all in one place, close to the family business’s office at Leehove.

The new research facility fits in with the growth plans of the company, which develops and supplies biocontrol agents. “We believe in the power of nature,” Thorben Looije says. “We develop natural crop protection products to make crops resilient to plant diseases. This is a perfect fit within the goals of a greener Europe, but also those of growers, who also attach importance to health, sustainability and the environment.”

Natural protection
The government uses Green Deals to encourage companies to reduce their impact on the environment. For greenhouse horticulture and agriculture, this means using more natural crop protection. Valto wants to respond to this need by conducting more research and tests and developing new biocontrol agents. The new greenhouse will make this possible in the future.

Innovation in legislation
According to Thorben, a condition for innovation is that legislation innovates too: “Our customers want a healthy harvest and good returns. They ask us to help them prevent diseases in their crops. We are happy to do that with the help of nature, but then the legislation has to be adapted. The approval procedure for natural crop protection products now takes about 8 to 10 years. Fortunately, more and more people in The Hague and Brussels are realizing that legislation must grow along with us if we want to meet the European goals.”

Continue Reading

Crop protection

Innovative strategies for biological control

Year after year, the number of crop protection and chemical products that can be employed to counter pathogens and harmful insects in agriculture gets smaller and smaller. Within that scenario and with the aim of achieving a more sustainable management of resources in line with the objectives of Agenda 2030, biological control using useful predators is the only solution.

It is with this purpose in mind that Agri Impo Tech was established in 2019 as an offshoot of Agri Impol in Battipaglia (Salerno), which boasts thirty years of experience in the preparation of pollination programs using bees and bumblebees.

“What is new in the world of biological control is the possibility of feeding mites and useful insects right after they are introduced. This way, they can develop before the attack of harmful insects. This strategy means useful insects can be launched even if their counterparts are not present yet. Nutrimite, distributed by Agri Impol Tech, has led to excellent results,” reports Antonio Rago, owner of Agri Impol and Agri Impol Tech.

For the past 30 years, Antonio Rago and his company have worked to make agriculture as sustainable as possible developing strategies with a low environmental impact. Agri Impol and Biobest have in fact signed an agreement for the sale and distribution of hives of Flying Doctor bumblebees and of all insects useful for biological control.

“Tuta Trap is a pheromone trap that attracts Tuta absoluta adult males. It can be used to monitor and mass capture parasite lepidoptera. Capturing males, in fact, noticeably reduces infestations dropping them to an acceptable level. 15/20 traps per hectare are needed in greenhouses and 15/25 per hectare in open fields. These can also be combined with color insect traps for monitoring and mass capturing.”

Another objective for the company is making producers understand the importance of pollination, which represents a crucial phase for setting and, therefore, for production.

“Nature alone is not enough to meet pollination needs, this is why we suggest introducing bees and bumblebees during blossoming. We are basically talking about buzz-pollination (especially for tomatoes) carried out by bumblebees, who are more stationary than bees and able to work at lower temperatures and in less-ideal weather (wind and rain). Bees are more suitable for late blossoming.”

“Apipol box has become available this year, i.e a hive containing two bee colonies. It was developed to favor entomophilous pollination in open-field crops and we will showcase it during Macfrut.”

“We will welcome you at Macfrut, stand 111, hall B5 to present our new company established in 2019 – Agri Impol Tech.”

Do you wish to create a pollination program perfect for you or get to know biological control options? The company will welcome you at Macfrut on September 7-9, 2021.

For further information:
Agri Impol s.r.l.
via Milano
84090 Montecorvino Pugliano (SA) -Italy
+39 0828 53744
+39 0828 507182

Continue Reading